1. Field of the Invention
The present invention relates to hearing aids. The invention, more specifically, relates to a binaural hearing aid system. The invention further relates to a method of initializing a binaural hearing aid system.
In the context of the present disclosure, a hearing aid should be understood as a small, microelectronic device designed to be worn behind or in the human ear by a hearing-impaired user. Prior to use, the hearing aid is adjusted by a hearing aid fitter according to a prescription. The prescription is based on a hearing test, resulting in a so-called audiogram, of the performance of the hearing-impaired user's unaided hearing. The prescription is developed to reach a setting where the hearing aid will alleviate a hearing loss by amplifying sound at frequencies in those parts of the audible frequency range where the user suffers a hearing deficit. A hearing aid comprises one or more microphones, a battery, a microelectronic circuit comprising a signal processor, and an acoustic output transducer. The signal processor is preferably a digital signal processor. The hearing aid is enclosed in a casing suitable for fitting behind or in a human ear.
A binaural hearing aid system comprises two hearing aids and is for use by a hearing-impaired person who suffers a hearing deficit on both ears. In most cases the hearing deficit is not the same for the two ears.
2. The Prior Art
U.S. Pat. No. 6,549,633 B1 discloses a binaural digital hearing aid system characterized in that the digital signal processing means of each hearing aid unit is arranged to effect a substantially full digital signal processing including individual processing of signals from the input transducer means of the actual unit and simulated processing of signals from the input transducer means of the other unit as well as binaural signal processing of signals supplied, on one hand, internally from the input signal transducer means of the same unit and, on the other hand, via a communication link from the input signal transducer means of the other unit. Hereby each of the hearing aid units, for the left and right side ears respectively, perform in addition to digital signal processing adapted to compensate for the hearing loss of the ear served by the unit, a simulated full digital signal processing of sound signals received by the unit for the opposite ear and adapted to compensate for the specific hearing loss of that ear, as well as a common binaural signal processing taking into account both of the normally different compensation characteristics of both units.
It is well known, for a hearing aid fitter, to program each one among a pair of hearing aids with a set of individualized adjustment data adapted to the specific compensation requirements of the corresponding ear of the intended user. This data set includes e.g. filter coefficients for the filters in the signal processing path. If, in addition to the above, a second set of individualized adjustment data adapted to the specific compensation requirements of the other ear of the intended user is to be programmed into each one among the same pair of hearing aids, then the hearing aid fitting practice would need to be changed because the hearing aid fitter must take care that both sets of individualized adjustment data would be stored in both hearing aids. This would increase the time that the hearing aid fitter needs to spend on each fitting.
Sometimes one of the two hearing aids of a binaural hearing aid system fails and needs repair. In case the hearing impaired user is given a replacement for the failed hearing aid, the replacement hearing aid normally needs to be programmed by a hearing aid fitter in accordance with the specific compensation requirements of the hearing aid user.
It is therefore a feature of the present invention to overcome at least these drawbacks and provide a method for initialization of a binaural hearing aid system, and a hearing aid and a binaural hearing aid system adapted for operating according to such a method.